More than one in eight American men between the ages of 25 and 49 experience some form of infertility today, according to the current data out of the U.S. Department of Health and Human Services. The problem, truly global in scope, has prompted millions in public and private research—and some of it appears to be paying off. A Utah-based biotech firm, aided by the Mayo Clinic, announced this week that it has successfully grown mature sperm, ready to swim, out of spermatogonial stem cells in the lab. According to the company, Paterna Biosciences, the technique could soon assist men struggling with infertility to conceive biological children. Paterna, in fact, also reported that it has already successfully tested its lab-grown sperm in the generation of (at least, provisionally) healthy-looking human embryos. “This is huge,” according to Baylor College urologist Larry Lipshultz, a specialist in male reproductive health who commented on the new research as an outside expert for Wired.…